Solve for $x$ and $y$ using substitution. ${-3x+2y = 12}$ ${x = -3y+7}$
Explanation: Since $x$ has already been solved for, substitute $-3y+7$ for $x$ in the first equation. ${-3}{(-3y+7)}{+ 2y = 12}$ Simplify and solve for $y$ $9y-21 + 2y = 12$ $11y-21 = 12$ $11y-21{+21} = 12{+21}$ $11y = 33$ $\dfrac{11y}{{11}} = \dfrac{33}{{11}}$ ${y = 3}$ Now that you know ${y = 3}$ , plug it back into $\thinspace {x = -3y+7}\thinspace$ to find $x$ ${x = -3}{(3)}{ + 7}$ $x = -9 + 7$ ${x = -2}$ You can also plug ${y = 3}$ into $\thinspace {-3x+2y = 12}\thinspace$ and get the same answer for $x$ : ${-3x + 2}{(3)}{= 12}$ ${x = -2}$